Method and apparatus for transmitting channel state information

ABSTRACT

A method of a terminal for transmitting channel state information for one or more beams comprises the steps of: determining whether group-based beam reporting is configured based on channel state information (CSI) reporting configuration information; measuring reference signal received power (RSRP) for one or more channel state information reference signals (CSI-RS) received through one or more CSI-RS resources; and transmitting, to a base station, the channel state information including a value in a table configured in advance based on whether the group-based beam reporting is configured and one or more CSI-RS RSRP measurement results obtained by the measurement.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.17/052,919 filed on Nov. 4, 2020, which is a National Stage Entry of PCTInternational Application No. PCT/KR2019/005910, which was filed on May17, 2019, and which claims priority from and the benefit of KoreanPatent Application No. 10-2018-0056360 filed with the KoreanIntellectual Property Office on May 17, 2018, Korean Patent ApplicationNo. 10-2018-0056363 filed with the Korean Intellectual Property Officeon May 17, 2018, Korean Patent Application No. 10-2018-0056370 filedwith the Korean Intellectual Property Office on May 17, 2018, KoreanPatent Application No. 10-2018-0056371 filed with the KoreanIntellectual Property Office on May 17, 2018, Korean Patent ApplicationNo. 10-2018-0056366 filed with the Korean Intellectual Property Officeon May 17, 2018, and Korean Patent Application No. 10-2019-0057396 filedwith the Korean Intellectual Property Office on May 16, 2018, the entirecontents of which are incorporated herein by reference. In addition,this non-provisional application claims priorities in countries otherthan the U.S. for the same reason based on the Korean PatentApplications, the entire contents of which are hereby incorporated byreference.

TECHNICAL FIELD

The present disclosure relates to terminals, base stations, and methodsfor transmitting and receiving channel state information.

BACKGROUND ART

As communication systems have been developed, various types of wirelessterminals have been introduced to consumers such as companies andindividuals.

Mobile communication systems employing technologies related to 3rdgeneration partnership project (3GPP), such as long term evolution(LTE), LTE-Advanced, fifth generation (5G), or the like, have beendesigned for transmitting and receiving a large amount of various data,such as video data, radio data, etc. at a high speed, beyondvoice-oriented communication.

After LTE-Advanced, technologies for next generation radio accessnetworks have been developed for enabling a terminal such as a userequipment as in the 3GPP to transmit and receive a larger amount of dataand provide a higher quality of service (QoS). For example, work ondevelopment of a so-called 5G network by the 3GPP is in progress.

In particular, in order to perform communication using a high frequencyband and provide high rate data transmission and reception services tomore terminals, the 5G network employs an analog beamforming technology.In the case of analog beamforming, a beam operation related technologyis needed for forming an optimal beam pair between a base station and aterminal through beam sweeping transmission and beam repetitiontransmission of the base station and the terminal.

In this case, in order for a base station to identify a channel state ofone or more beams, a terminal is needed to measure a channel transmittedin the form of multiple beams, and transmits measurement information ona result of the measurement to the base station. At this time, it shouldbe noted that in a situation where multiple beams are operated, overheadof an associated system may increase due to the increase of signalsneeded to transmit measurement results for beams to the base station.

Accordingly, it is desired to provide a new method for enabling aterminal to transmit channel state information for one or more beams toa base station.

DETAILED DESCRIPTION OF THE INVENTION Technical Problem

In accordance with embodiments of the present disclosure, a method isprovided for enabling a terminal to transmit channel state informationfor one or more beams to a base station.

Technical Solution

In one aspect of the present disclosure, according to embodiments, amethod of a terminal is provided for transmitting channel stateinformation for one or more beams, the method comprising: receivingchannel state information (CSI) reporting configuration information froma base station; determining whether group-based beam reporting isconfigured based on the CSI reporting configuration information;measuring reference signal received power (RSRP) for one or more CSI-RSsreceived through one or more CSI-RS resources; and transmitting, to thebase station, channel state information including a value in a tableconfigured in advance based on whether the group-based beam reporting isconfigured and one or more CSI-RS RSRP measurement results obtained bythe measurement.

In another aspect of the present disclosure, according to embodiments, amethod of a base station is provided for receiving channel stateinformation for one or more beams, the method comprising: transmittingCSI reporting configuration information to a terminal; and when it isdetermined that group-based beam reporting is used based on the CSIreporting configuration information, receiving channel state informationincluding two or more CSI-RS RSRP measurement results, the two or moreCSI-RS RSRP measurement results being included in the channel stateinformation as values in a table configured in advance in the terminal,the pre-configured table including a table for indicating one of CSI-RSRSRP measurement results and a table for indicating at least onedifferential CSI-RS RSRP measurement result.

In further another aspect of the present disclosure, according toembodiments, a terminal is provided for transmitting channel stateinformation for one or more beams, the terminal comprising: a receiverreceiving CSI reporting configuration information from a base station; acontroller determining whether group-based beam reporting is configuredbased on the CSI reporting configuration information, and measuring RSRPfor one or more CSI-RSs received through one or more CSI-RS resources;and a transmitter transmitting, to the base station, channel stateinformation including a value in a table configured in advance based onwhether the group-based beam reporting is configured and one or moreCSI-RS RSRP measurement results.

Effects of the Invention

In accordance with embodiments of the present disclosure, it is possibleto provide an effect of transmitting channel state information, whilereducing the load of an associated system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram schematically illustrating a structure of a NRwireless communication system according to embodiments of the presentdisclosure.

FIG. 2 is a diagram illustrating a frame structure of the NR systemaccording to embodiments of the present disclosure.

FIG. 3 is a diagram illustrating a resource grid supported by a radioaccess technology according to embodiments of the present disclosure.

FIG. 4 is a diagram illustrating a bandwidth part supported by the radioaccess technology according to embodiments of the present disclosure.

FIG. 5 is a diagram illustrating an example of a synchronization signalblock in the radio access technology according to embodiments of thepresent disclosure.

FIG. 6 is a diagram illustrating a random access procedure in the radioaccess technology according to embodiments of the present disclosure.

FIG. 7 is a diagram illustrating CORESETs.

FIG. 8 is a flow diagram illustrating operation of a terminal accordingto embodiments of the present disclosure.

FIG. 9 is a diagram illustrating an information element of CSI reportingconfiguration information according to embodiments of the presentdisclosure.

FIGS. 10 to 13 are diagrams illustrating examples of RSRP tablesconfigured in advance according to embodiments of the presentdisclosure.

FIGS. 14 and 15 are diagrams illustrating group-based beam reportingoperation for multiple beams according to embodiments of the presentdisclosure.

FIGS. 16 and 17 are diagrams illustrating examples of differential RSRPtables according to embodiments of the present disclosure.

FIG. 18 is a flow diagram illustrating operation of a base stationaccording to embodiments of the present disclosure.

FIGS. 19 and 20 are diagrams illustrating a MAC CE for power headroomreporting according to embodiments of the present disclosure.

FIG. 21 is a block diagram illustrating a terminal in accordance withembodiments of the present disclosure.

FIG. 22 is a block diagram illustrating a base station according toembodiments of the present disclosure.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present preferred embodiments of the disclosure will bedescribed in detail with reference to the accompanying drawings. Indenoting elements of the drawings by reference numerals, the sameelements will be referenced by the same reference numerals even when theelements are illustrated in different drawings. Further, in thefollowing description of the present disclosure, detailed discussions onknown functions and configurations incorporated herein may be omittedwhen it is desired to focus on the subject matter of the presentdisclosure. The terms such as “including”, “having”, “containing”,“comprising of”, and “consist of” used herein are generally intended toallow other components to be added unless the terms are used with theterm “only”. Singular forms used herein are intended to include pluralforms unless the context clearly indicates otherwise.

Further, the terms “first”, “second”, “A”, “B”, “(a)”, “(b)”, or thelike may be used to describe elements included in embodiments of thepresent disclosure. Each of the terms is not used to define essence,order, sequence, or number of an element, but is used merely todistinguish the corresponding element from another element.

Herein, situations in which two or more elements included in embodimentsof the present disclosure are connected, combined, coupled, contacted,or the like may include not only directly or physically connecting,combining, coupling, or contacting between two or more elements, butinterposing of another element between the two or more elements. Here,the another element may be included in one or more of the two or moreelements connected, combined, coupled, or contacted (to) one another.

In describing time relative terms with reference to elements,operations, steps, or processes included in embodiments of the presentdisclosure, situations in which “after”, “subsequent to”, “next to”,“before”, or the like is used to describe a temporal sequentialrelationship or a flow sequential relationship between events,operations, or the like are generally intended to include events,situations, cases, operations, or the like that do not occurconsecutively unless the terms, such as “directly”, “immediately”, orthe like, are used.

Meanwhile, when numerical values for elements included in embodiments ofthe present disclosure or their associated information (e.g., levelsetc.) are described, even when specific relevant descriptions are notgiven, the numerical values or the associated information may beinterpreted as including a margin of error that can be caused by severalfactors (e.g., factors in the process, internal or external impact,noise, etc.).

The wireless communication systems in the present disclosure refer tosystems for providing various communication services using radioresources, such as a voice service, a data packet service, etc., and mayinclude a terminal, a base station, a core network, and the like.

Embodiments described below may be applied to wireless communicationsystems using various radio access technologies. For example,embodiments of the present disclosure may be applied to various radioaccess technologies, such as code division multiple access (CDMA),frequency division multiple access (FDMA), time division multiple access(TDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), non-orthogonalmultiple access (NOMA) or the like. Further, the radio accesstechnologies may denote not only a specific multiple access technology,but also a communication technology for each generation developed byvarious communication organizations such as 3GPP, 3GPP2, Wi-Fi,Bluetooth, IEEE, ITU, or the like. For example, the CDMA may beimplemented with radio technologies, such as universal terrestrial radioaccess (UTRA), CDMA2000, or the like. The TDMA may be implemented withradio technologies, such as global system for mobile communications(GSM), general packet radio service (GPRS), enhanced data rates for GSMevolution (EDGE), or the like. The OFDMA may be implemented with radiotechnologies, such as institute of electrical and electronics engineers(IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, evolved UTRA(E-UTRA), or the like. The IEEE 802.16m is the evolvement of IEEE802.16e, and supports backward compatibility with a system based on theIEEE 802.16e. The UTRA is a part of the universal mobiletelecommunications system (UMTS). 3rd generation partnership project(3GPP) long term evolution (LTE) is a part of E-UMTS (evolved UMTS)using evolved-UMTS terrestrial radio access (E-UTRA), and employs theOFDMA in downlink and the SC-FDMA in uplink. As described above,embodiments of the present disclosure may be applied to radio accesstechnologies that are currently being launched or commercialized, orthat are being developed or will be developed in the future.

Meanwhile, in the present disclosure, the term “terminal” is defined asa generic term meaning a device including a wireless communicationmodule performing communications with a base station in a wirelesscommunication system, and shall be construed as including, but notlimited to, all of devices, such as, not only a user equipment (UE)supporting wideband code division multiple access (WCDMA), LTE, newradio (NR, referred to as next-generation/5G radio access technology),high speed packet access (HSPA), international mobile telecommunications(IMT)-2020 (5G or new radio), or the like, but a mobile station (MS)supporting the GSM, a user terminal (UT), a subscriber station (SS), awireless device, or the like. Further, according to types of being used,the terminal may denote a user portable device such as a smart phone, ora vehicle, a device including a wireless communication module in thevehicle, or the like in a V2X communication system. Further, in the caseof a machine type communication (MTC) system, the terminal may denote anMTC terminal, an M2M terminal, a ultra-reliable and low latencycommunications (URLLC) terminal, or the like, on which a communicationmodule enabling machine type communication to be performed is mounted.

In the present disclosure, the term “base station” or “cell” generallyrefers to a station communicating with a terminal in a communicationnetwork. The base station or cell is defined as a generic termincluding, but not limited to, all of various coverage areas, such as aNode-B, an evolved Node-B (eNB), a gNode-B (gNB), a low power node(LPN), a sector, a site, various types of antennas, a base transceiversystem (BTS), an access point, a point (e.g., a transmitting point, areceiving point, or a transceiving point), a relay node, a megacell, amacrocell, a microcell, a picocell, a femtocell, a remote radio head(RRH), a radio unit (RU), a small cell, or the like. Further, the cellmay denote including a bandwidth part (BWP) in the frequency domain. Forexample, a serving cell may denote an activation BWP of a terminal.

Each of these various cells is controlled by a base station controllingone or more cells. Therefore, the base station may be classified intotwo types. 1) One type of the base station may denote an apparatusproviding a megacell, a macrocell, a microcell, a picocell, a femtocell,or a small cell that forms a communication service area, and 2) theother type of the base station may denote the communication servicearea. Apparatuses that form and provide a certain radio area, and thatare controlled by one or more identical entities or that interact withone another for enabling two or more entities to cooperate with oneanother to provide the radio area may be referred to as the type 1) basestation. A point, a transmission/reception point, a transmission point,a reception point, or the like may be an example of such base stationaccording to methods of configuring radio areas. A radio area itself towhich a terminal or a neighboring base station transmits a signal orfrom which the terminal or the neighboring base station receives asignal may be referred to as the type 2) base station.

In the present disclosure, the cell may denote a coverage of a signaltransmitted from a transmission/reception point, a component carrierhaving a coverage of a signal transmitted from a transmission point or atransmission/reception point, or a transmission/reception point itself.

Uplink (UL) denotes a scheme of enabling a terminal to transmit data to,or receive data from, a base station, and downlink (DL) denotes a schemeof enabling the base station to transmit data to, or receive data from,the terminal. The downlink may denote communication or a communicationpath from multiple transmission/reception points to a terminal, and theuplink may denote communication or a communication path from theterminal to the multiple transmission/reception points. In the downlink,a transmitter may be a part of multiple transmission/reception points,and a receiver may be a part of a terminal. In the uplink, a transmittermay be a part of a terminal and a receiver may be a part of multipletransmission/reception points.

Control information can be transmitted and/or received through theuplink and/or the downlink configured with a control channel, such as aphysical downlink control channel (PDCCH), a physical uplink controlchannel (PUCCH), and the like, and data can be transmitted through theuplink and/or the downlink configured with a data channel, such as aphysical downlink shared channel (PDSCH), a physical uplink sharedchannel (PUSCH), and the like. Hereinafter, a situation where a signalis transmitted or received through a channel such as the PUCCH, thePUSCH, the PDCCH, or the PDSCH, may be expressed as the transmission orreception of the PUCCH, the PUSCH, the PDCCH, or the PDSCH.

Hereinafter, to describe clearly embodiments of the present disclosure,related description will be given based on, but is not limited to, the3GPP long term evolution (LTE)/long term evolution-A (LTE-A)/new radio(New RAT,“NR”) communication system.

After 4th-generation (4G) communication technology has been developed,the development of 5th-generation (5G) communication technologyorganized by the 3GPP is in progress in order to meet requirements fornext generation radio access technology under the ITU-R. Specifically,according to work organized by the 3GPP, a new NR communicationtechnology as 5G communication technology has been developedindependently of LTE-A pro that is evolved from LTE-Advanced technologyto meet requirements of the ITU-R and 4G communication technology. Eventhough 5G communication technology herein includes the LTE-A pro and theNR, for convenience of description, unless explicitly stated otherwise,embodiments in the present disclosure will be discussed by focusing onthe NR as the 5G communication technology.

Various operation scenarios of the NR are defined by adding scenariosfor a satellite, a vehicle, a new vertical, and the like, in typical 4GLTE scenarios. In service aspects of the scenarios, the NR supports anenhanced mobile broadband (eMBB) scenario, a massive machinecommunication (mMTC) scenario that is characterized by a high density ofterminals and a wide range of deployment and provides a low data rateand asynchronous access, and an ultra-reliability and Low latency(URLLC) scenario that is characterized by high responsiveness andreliability and provides high rate mobility.

To satisfy such scenarios, the NR specifies wireless communicationsystems to which at least one of a new waveform and frame structuretechnology, a low latency technology, a ultra-high frequency band(mmWave) support technology and a forward compatible providing techniqueis applied. In particular, in order to provide forward compatibility, ina flexibility aspect, various technological changes have been introducedinto the NR system. Main technical features of the NR are describedbelow with reference to the accompanying drawings.

<General NR System>

FIG. 1 is a diagram schematically illustrating a structure of a NRsystem where embodiments of the present disclosure may be applied.

Referring to FIG. 1 , the NR system is divided into a 5G core network(5GC) and an NR-RAN part. The NG-RAN includes a gNB providing user plane(SDAP/PDCP/RLC/MAC/PHY) and control plane (RRC) protocol terminationstoward a terminal, i.e. a user equipment and an ng-eNB providing E-UTRAuser plane and control plane protocol terminations towards the terminal.Interconnection between gNBs or between the gNB and the ng-eNB isperformed via a Xn interface. Each of the gNB and the ng-eNB isconnected to the 5GC via an NG interface. The 5GC may include an accessand mobility management function (AMF) in charge of a control plane of aterminal access and mobility control function, and the like, and a userplane function (UPF) in charge of a control function for user data. TheNR supports both a frequency range of 6 GHz or less (FR1, FrequencyRange 1) and a frequency range of 6 GHz or more (FR2, Frequency Range2).

The gNB denotes a base station providing NR user plane and control planeprotocol terminations toward a terminal, and the ng-eNB denotes a basestation providing E-UTRA user plane and control plane protocolterminations toward a terminal. Base stations described herein should beinterpreted as including both the gNB and the ng-eNB, and may be alsoused as either the gNB or the ng-eNB, when needed.

<NR Waveform, Numerology and Frame Structure>

In the NR, CP-OFDM waveform using cyclic prefix is used for DLtransmission, and CP-OFDM or DFT-s-OFDM is used for UL transmission. TheOFDM technology has advantages that can be easily combined with multipleinput multiple output (MIMO), and that can use a receiver with highfrequency efficiency and low complexity.

Meanwhile, the NR specifies different requirements for data rate,latency, coverage, etc. for each of the three scenarios described above;therefore, it is necessary to efficiently satisfy the requirements foreach scenario through a frequency band configured for an NR system. Todo this, a technology has been proposed for efficiently multiplexing aplurality of numerology-based radio resources different from oneanother.

Specifically, NR transmission numerology is determined based onsubcarrier spacing and cyclic prefix (CP), and a μ value is used as anexponential value of 2 based on 15 kHz and exponentially changed, asshown in Table 1 below.

TABLE 1 Subcarrier Cyclic Supported Supported μ spacing prefix for datafor synch 0 15 Normal Yes Yes 1 30 Normal Yes Yes 2 60 Normal, ExtendedYes No 3 120 Normal Yes Yes 4 240 Normal No Yes

As shown in Table 1 above, the NR numerology can be classified into fivetypes according to the subcarrier spacing. This is different from theLTE, one of the 4G communication technologies, where subcarrier spacingis fixed at 15 kHz. Specifically, in the NR, subcarrier spacings usedfor data transmission are 15, 30, 60, and 120 kHz, and subcarrierspacings used for synchronous signal transmission are 15, 30, 120, and240 kHz. Also, an extended CP is applied to only the 60 kHz subcarrierspacing. Meanwhile, a frame with a length of 10 ms including 10subframes each having a length of 1 ms identical to one another isdefined in the frame structure of the NR. One frame can be divided intohalf frames of 5 ms, and each half frame includes 5 subframes. In thecase of the 15 kHz subcarrier spacing, one subframe is made up of oneslot and each slot is made up of 14 OFDM symbols. FIG. 2 is a diagramillustrating the frame structure of the NR system according toembodiments of the present disclosure. Referring to FIG. 2 , a slot isfixedly made up of 14 OFDM symbols in the case of normal CP, but alength of the slot in the time domain may be different depending onsubcarrier spacings. For example, in the case of a numerology with the15 kHz subcarrier spacing, one slot has a length of 1 ms identical tothe subframe. In the case of numerology with the 30 kHz subcarrierspacing, while one slot is made up of 14 OFDM symbols, the slot has alength of 0.5 ms, and two slots can be included in one subframe. Thatis, as the subframe and the frame are defined to have a fixed timelength, and the slot is defined by the number of symbols, a time lengthof the slot may be different according to subcarrier spacings.

Meanwhile, NR defines a slot as a basic unit of scheduling and alsointroduces a minislot (or a subslot or a non-slot based schedule) toreduce a transmission delay in the radio section. When a wide subcarrierspacing is used, since a length of one slot is inversely shortened, itis therefore possible to reduce a transmission delay in the radiosection. The minislot (or subslot) is for efficient support for theURLLC scenario and can be scheduled based on 2, 4, or 7 symbols.

Further, unlike the LTE, the NR defines uplink and downlink resourceallocations based on a symbol level within one slot. In order to reduceHARQ latency, a slot structure of allowing HARQ ACK/NACK to be directlytransmitted in a transmission slot is defined, and this slot structureis referred to as a self-contained structure for description.

In the NR, the slot structure has been designed to enable a total of 256slot formats to be supported, of which 62 slot formats are used in 3GPPRel-15. Further, a common frame structure of allowing an FDD or TDDframe to be configured through various combinations of slots issupported in the NR. For example, the NR supports a slot structure inwhich all symbols of a slot are configured in downlink, a slot structurein which all symbols of a slot are configured in uplink, and a slotstructure in which downlink symbols and uplink symbols are combined.Further, the NR supports that data transmission is scheduled such thatdata are distributed in one or more slots. Accordingly, a base stationmay inform a terminal whether a corresponding slot is a downlink slot,an uplink slot, or a flexible slot, using a slot format indicator (SFI).The base station may indicate the slot format i) by indicating an indexof a table configured through UE-specific RRC signaling, using the SFI,ii) dynamically through downlink control information (DCI), or iii)statically or quasi-statically through RRC.

<NR Physical Resources>

An antenna port, a resource grid, a resource element, a resource block,a bandwidth part, or the like is considered with respect to physicalresources in the NR.

The antenna port is defined such that a channel on which a symbol on anantenna port is carried can be inferred from a channel on which anothersymbol on the same antenna port is carried. If a large-scale property ofa channel carrying a symbol on one antenna port can be inferred from achannel on which a symbol on another antenna port is carried, the twoantenna ports may be in a quasi co-located or quasi co-location (QC/QCL)relationship. Here, the large-scale property includes at least one of adelay spread, a Doppler spread, a frequency shift, an average receivedpower, and a received timing.

FIG. 3 is a diagram illustrating a resource grid supported by the radioaccess technology according to embodiments of the present disclosure.

Referring to FIG. 3 , since the NR supports a plurality of numerologiesin an identical carrier, a resource grid can be configured according toeach numerology. Further, the resource grid may be configured dependingon an antenna port, a subcarrier spacing, and a transmission direction.

A resource block is made up of 12 subcarriers and is defined only in thefrequency domain. Further, a resource element is made up of one OFDMsymbol and one subcarrier. Therefore, as shown in FIG. 3 , a size of oneresource block may vary according to the subcarrier spacings. Further,the NR defines “Point A” that serves as a common reference point forresource block grids, a common resource block, and a virtual resourceblock.

FIG. 4 is a diagram illustrating a bandwidth part supported by the radioaccess technology according to embodiments of the present disclosure.

Unlike to the LTE in which a carrier bandwidth is fixed at 20 Mhz, inthe NR, a maximum carrier bandwidth is configured from 50 Mhz to 400 Mhzfor each subcarrier spacing. Therefore, it is not assumed that allterminals may use all of these carrier bandwidths. Thus, as shown inFIG. 4 , in the NR, a terminal is allowed to designate and use abandwidth part within a carrier bandwidth. Further, the bandwidth partmay be associated with one numerology, be made up of consecutive subsetsof the common resource block, and be activated dynamically over time.For a terminal, a maximum of four bandwidth parts are configured in eachof uplink and downlink, and data can be transmitted or received using anactivated bandwidth part at a given time.

In the case of a paired spectrum, the uplink and downlink bandwidthparts are configured independently. In the case of an unpaired spectrum,the downlink and uplink bandwidth parts are configured in pairs toenable a center frequency to be shared to prevent unnecessary frequencyre-tuning between downlink and uplink operations.

<NR Initial Access>

In the NR, a terminal performs cell search and random access proceduresto access a base station and perform communication.

The cell search is a procedure for enabling a terminal to synchronizewith a cell of an associated base station using a synchronization signalblock (SSB) transmitted by the base station, obtain a physical layercell ID, and obtain system information.

FIG. 5 is a diagram illustrating an example of a synchronization signalblock in the radio access technology according to embodiments of thepresent disclosure.

Referring to FIG. 5 , the SSB includes a primary synchronization signal(PSS) and a secondary synchronization signal (SSS), each of whichoccupies one symbol and 127 subcarriers, and a PBCH configured on threeOFDM symbols and 240 subcarriers.

A terminal monitors the SSB in time and frequency domains and receivesthe SSB.

The SSB may be transmitted up to 64 times for 5 ms. A plurality of SSBsare transmitted through different transmission beams within 5 msduration, and the terminal detects the SSBs, assuming that the SSBs aretransmitted every 20 ms period based on a specific one beam used fortransmission. The higher the frequency band is, the greater the numberof beams that can be used for SSB transmission within 5 ms duration canincrease. For example, the SSBs can be transmitted using i) a maximum offour different beams in a frequency band of 3 GHz or lower, ii) amaximum of 8 different beams in a frequency band of 3 GHz to 6 GHz, andiii) a maximum of 64 different beams in a frequency band of 6 GHz orhigher.

Two SSBs are included in one slot, and a start symbol and the number ofrepetitions in a slot are determined according to subcarrier spacings asdescribed below.

Meanwhile, the SSB is not transmitted at a center frequency of a carrierbandwidth unlike the SSB of the LTE. That is, the SSB may be transmittedon a frequency that is not the center of a system band, and a pluralityof SSBs may be transmitted in the frequency domain in a situation wherewideband operation is supported. According to this, the terminalmonitors a SSB using a synchronization raster, which is a candidatefrequency position for monitoring the SSB. A carrier raster and thesynchronous raster, which are center frequency position information of achannel for initial access, are newly defined in the NR. Since thesynchronous raster is configured with a wide frequency interval comparedwith the carrier raster, thus, the synchronous raster can support rapidSSB search of the terminal.

The terminal may acquire a master information block (MIB) through a PBCHof the SSB. The MIB includes minimum information for enabling theterminal to receive remaining minimum system information (RMSI)broadcast by an associated network. Further, the PBCH may includeinformation on a position of a first DM-RS symbol in the time domain,information for allowing the terminal to monitor system informationblock 1 (SIB1) (for example, SIB1 numerology information, SIB1 CORESETrelated information, search space information, physical downlink controlchannel (PDCCH) related parameter information, etc.), offset informationbetween a common resource block and a SSB (an absolute position of theSSB in a carrier is transmitted via the SIB1), and the like. Here, theSIB1 numerology information is equally applied to one or more messagesused in a random access procedure for accessing a base station after theterminal has completed the cell search procedure. For example,numerology information of the SIB1 may be applied to one of messages 1to 4 for the random access procedure.

The RMSI may denote system information block 1 (SIB1), and the SIB1 isbroadcast periodically (ex, 160 ms) in a corresponding cell. The SIB1includes information needed for the UE to perform an initial randomaccess procedure, and is periodically transmitted through a PDSCH. Inorder to receive the SIB1, the terminal is required to receivenumerology information used for SIB1 transmission and control resourceset (CORESET) information used for SIB1 scheduling, through the PBCH.The terminal identifies the scheduling information for the SIB1 using aSI-RNTI in the CORESET, and acquires the SIB1 on the PDSCH according tothe scheduling information. Remaining SIBs except for the SIB1 may betransmitted periodically or may be transmitted according to a request ofa UE.

FIG. 6 is a diagram illustrating a random access procedure available inthe radio access technology according to embodiments of the presentdisclosure.

Referring to FIG. 6 , when cell search is completed, a terminaltransmits a random access preamble for random access to a base station.The random access preamble is transmitted through a PRACH. Specifically,the random access preamble is transmitted to the base station throughthe PRACH, which is made up of consecutive radio resources in a specificslot repeated periodically. Generally, a contention-based random accessprocedure is performed when a terminal initially accesses a cell, and anon-contention based random access procedure is performed when randomaccess is performed for beam failure recovery (BFR).

The terminal receives a random access response to the transmitted randomaccess preamble. The random access response may include a random accesspreamble identifier (ID), an uplink grant (uplink radio resource), atemporary cell-radio network temporary identifier (temporary C-RNTI),and a time alignment command (TAC). Since one random access response mayinclude random access response information for one or more terminals,the random access preamble identifier may be included to inform whichterminal the included uplink grant, the temporary C-RNTI and the TAC arevalid to. The random access preamble identifier may be an identifier ofa random access preamble received by the base station. The TAC may beincluded as information for enabling the terminal to adjust uplinksynchronization. The random access response may be indicated by a randomaccess identifier on a PDCCH, i.e., a random access-radio networktemporary identifier (RA-RNTI).

When receiving the valid random access response, the terminal processesinformation included in the random access response and performsscheduled transmission to the base station. For example, the terminalapplies the TAC and stores the temporary C-RNTI. Further, using the ULgrant, the terminal transmits data stored in a buffer or newly generateddata to the base station. In this case, information for identifying theterminal should be included.

The terminal receives a downlink message for contention resolution.

<NR Coreset>

A downlink control channel in the NR is transmitted on a controlresource set (CORESET) having a length of 1 to 3 symbols, and transmitsup/down scheduling information, slot format index (SFI) information,transmit power control (TPC) information, and the like.

Thus, in the NR, in order to secure the flexibility of the system, aconcept of the CORESET is introduced. The control resource set (CORESET)denotes a time-frequency resource for a downlink control signal. Theterminal may decode a control channel candidate using one or more searchspaces in a CORESET time-frequency resource. Quasi CoLocation (QCL)assumption is established for each CORESET, which is used for thepurpose of informing characteristics for analogue beam directions inaddition to characteristics assumed by typical QCL, such as delayedspread, Doppler spread, Doppler shift, or average delay.

FIG. 7 is a diagram illustrating a CORESET.

Referring to FIG. 7 , the CORESET may be configured in various formswithin a carrier bandwidth in one slot, and may be made up of a maximumof 3 OFDM symbols in the time domain. In addition, the CORESET isdefined as a multiple of six resource blocks up to a carrier bandwidthin the frequency domain.

A first CORESET is indicated through the MIB as a part of an initialbandwidth part configuration to enable additional configurationinformation and system information to be received from the network.After establishing a connection with a base station, a terminal mayreceive information on one or more CORESETs through RRC signaling.

In the present disclosure, a frequency, a frame, a subframe, a resource,a resource block (RB), a region, a band, a sub-band, a control channel,a data channel, a synchronization signal, various reference signals,various signals, or various messages associated with the NR may beinterpreted as terms or meanings that were used in the past or are usedin the present or as various terms or meanings that will be used in thefuture.

The terminal may receive a channel state information (CSI) referencesignal (CSI-RS), and then measure quality for a communication channelwith the base station. The CSI-RS is a signal transmitted by the basestation for estimating a channel state. In the present disclosure, theestimating of a channel state is discussed based on the CSI-RS; however,embodiments of the present disclosure are not limited thereto. Forexample, a channel state may be equally estimated based on asynchronization signal block (SSB). Further, hereinafter, a method ofmeasuring a channel is discussed based on reference signal receptionpower (RSRP); however, embodiments of the present disclosure are notlimited thereto. For example, a channel may be equally measured based onRSRQ, or the like.

When the terminal measures the CSI-RS, the terminal includes informationon measurement results in channel state information and transmits thechannel state information to the base station. The information on themeasurement results may include various information, such as, but notlimited to PMI, RI, and the like. The channel state information may betransmitted periodically or non-periodically, and transmitted through anuplink control channel or an uplink data channel.

Meanwhile, beamforming technology has been introduced in the NR(New-RAT) to which 5G communication technology is applied. This enablesvarious services to be provided for each terminal by establishing beamparing with a corresponding terminal using an analogue beamformingtechnique. To do this, a base station transmits multiple beams usingbeam sweeping, and performs a beam paring procedure with a terminal.

When the base station transmits multiple beams using the beam sweeping,it may be needed to obtain channel state information for each beam. Theterminal may measure channel states for multiple beams indicated by thebase station, and report these to the base station. A CSI-RS or an SSBin each beam may be used for measuring a channel state, and the basestation may indicate, to the terminal, resource information for a signalto be measured and a target to be measured.

In this case, when the terminal transmits channel measurement resultsfor each beam to the base station, transmitting all of the measurementresults of respective beams may cause an associated system to becomeoverloaded. Accordingly, in reporting channel measurement results formultiple beams to the base station, a new method is desired to minimizean overload of the system.

FIG. 8 is a flow diagram illustrating operation of a terminal accordingto embodiments of the present disclosure.

Referring to FIG. 8 , a method of enabling the terminal to transmitchannel state information for one or more beams may receive CSI reportconfiguration information from a base station, at step S800.

For example, the terminal may receive the CSI report configurationinformation through an RRC message from the base station. The CSI reportconfiguration information may include resource information on one ormore targets required to be measured by the terminal. Further, the CSIreport configuration information may include information on ameasurement method required to be used by the terminal. Further, the CSIreport configuration information may include parameters for indicating achannel state information transmission period or a trigger condition ofthe terminal, non-periodic transmission, or the like.

FIG. 9 is a diagram illustrating an information element of CSI reportingconfiguration information according to embodiments of the presentdisclosure.

Referring to FIG. 9 , the CSI reporting configuration information mayinclude group-based beam reporting parameters indicating whethergroup-based beam reporting is configured. For example, agroupBasedBeamReporting parameter may include a value indicatingenablement or disablement.

In another example, when a value of the groupBasedBeamReportingparameter is set to enablement, it may be determined that group-basedbeam reporting is configured. In another example, when a value of thegroupBasedBeamReporting parameter is not designated, a correspondingterminal may recognize this as enablement.

In another example, when a value of the groupBasedBeamReportingparameter is set to disablement, it may be determined that group-basedbeam reporting is not configured. When a value of thegroupBasedBeamReporting parameter is set to disablement, a valueindicating the number of measured CSI-RS resources to be includedchannel state information may be included. When the value of thegroupBasedBeamReporting parameter indicates the disablement, any one offour different values of indicating the number of measured CSI-RSresources to be included in channel state information may be set. Inthis case, the four different values may be set as 1, 2, 4, 8, and thelike; however, embodiments of the present disclosure are not limitedthereto.

For example, if the value of 2 is set in the groupBasedBeamReportingparameter, a corresponding terminal may recognize that group-based beamreporting is disabled, and the terminal is required to transmit 2 CSI-RSmeasurement results. That is, a situation where the terminal is requiredto transmit 1 CSI-RS measurement result corresponds to a case where thevalue of 1 is set in the groupBasedBeamReporting parameter.

The method of transmitting channel state information may determinewhether group-based beam reporting is used based on the received CSIreporting configuration information, at step S810.

For example, when the group-based beam reporting parameter is set toenablement, or a value indicating the number of measured CSI-RSresources to be included in channel state information is set as a valueexceeding 1, the terminal may determine that the group-based beamreporting is used. This means that a plurality of CSI-RS RSRPmeasurement results is included in channel state information transmittedby the terminal.

In another example, when the group-based beam reporting parameter is setto disablement, and a value indicating the number of measured CSI-RSresources to be included in channel state information is set as 1, theterminal may determine that the group-based beam reporting is not used.This may mean that only 1 CSI-RS RSRP measurement result is included inchannel state information transmitted by the terminal.

Through this, the terminal may determine the number of CSI-RS RSRPmeasurement results to be included in channel state information.

The method of transmitting channel state information may measure RSRPfor one or more CSI-RSs received through one or more CSI-RS resources,at step S820. The terminal may measure RSRP based on one or more CSI-RSstransmitted by the base station. The RSRP may be measured for each beamidentifier. The order in which the step S810 and the step S820 areperformed may be changed. That is, the step S820 is performed prior tothe step S810.

Meanwhile, the method of transmitting channel state information maytransmit channel state information including a value in a tableconfigured in advance based on whether the group-based beam reporting isused and the one or more CSI-RS RSRP measurement results, at step S830.

For example, the table configured in advance may include a table forindicating one CSI-RS RSRP measurement result and a table for indicatingat least one differential CSI-RS RSRP measurement result. That is, theterminal may configure one or more tables in advance for indicating aplurality of CSI-RS RSRP measurement results. The table configured inadvance may be received through an RRC message from the base station, orbe configured and stored in advance in the terminal.

The terminal may configure the channel state information according towhether the group-based beam reporting is used. To do this, the terminalmay determine any one of one or more tables configured in advance thatwill be used to select an index value.

Hereinafter, examples of tables configured in advance are described withreference to the accompanying drawings.

FIGS. 10 to 13 are diagrams illustrating examples of RSRP tablesconfigured in advance according to embodiments of the presentdisclosure.

Referring to FIG. 10 , a table for indicating one CSI-RS RSRPmeasurement result may be configured in 7 bits, and values in the rangeof [−140, −44] dBm may be divided and configured at 1 dB intervals.

Referring to FIG. 11 , a table for indicating one CSI-RS RSRPmeasurement result may be configured in 6 bits, and values in the rangeof [−140, −44] dBm may be divided and configured at 2 dB intervals.

Referring to FIG. 12 , a table for indicating one CSI-RS RSRPmeasurement result may be configured in 7 bits, and values in the rangeof [−140, −44] dBm may be divided and configured at 1 dB intervals or0.5 dB intervals. For example, the values in the range of [−140, −44]dBm may be configured at 1 dB intervals in one specific section and at0.5 dB intervals in the other section. In addition, such table may beconfigured at various dB intervals, and embodiments of the presentdisclosure are not limited thereto.

Referring to FIG. 13 , a table for indicating one CSI-RS RSRPmeasurement result may be configured in 7 bits, and values in the rangeof [−140, −44] dBm may be divided and configured at 1 dB intervals. Inthis case, in order for CSI-RSRP to be indicated together with the L3SS-RSRP table, the CSI-RSRP can be configured to be identified by beingmapped to the middle part of values of 7 bits. That is, RSRP 16 to RSRP113 may be configured to be used as identifiers for indicating theCSI-RS RSRP.

The above-described tables are examples for describing embodiments ofthe present disclosure, and an interval, a range, or the like may bevariously configured.

Referring back to FIG. 8 , when it is determined that the group-basedbeam reporting is not used, the terminal may include, in channel stateinformation, a value of 7 bits corresponding to a section in which oneCSI-RS RSRP measurement result is included from a table configured inadvance (e.g., FIG. 10 or FIG. 13 ) in which values in the range of[−140, −44] dBm are broken down and set at 1 dB intervals, and thentransmit the channel state information including the value of 7 bits.

Meanwhile, when it is determined that the group-based beam reporting isused, including values of 7 bits for each measurement result in channelstate information may lead an amount of data in the channel stateinformation to be overloaded.

FIGS. 14 and 15 are diagrams illustrating group-based beam reportingoperation for multiple beams according to embodiments of the presentdisclosure.

Referring to FIG. 14 , when the number of L beam groups including Q beamIDs is present, if a terminal measures RSRP for each beam ID, theterminal is required to include, in channel state information, each of amaximum of (L X Q) RSRP values in 7 bits, and transmit the channel stateinformation.

To address such issue, the channel state information may be transmittedusing a value in a differential CSI-RS RSRP table for each beam group.

Referring to FIG. 15 , a terminal may determine a reference RSRP valuebased on an RSRP value for one beam ID for each beam group, and thenindicate an RSRP value for another beam ID included identical beam groupas a difference from the reference RSRP value. Through this, it ispossible to reduce the overload of an amount of data caused bytransmitting channel state information including RSRP values for allbeam IDs in 7 bits.

For example, when it is determined that the group-based beam reportingis used, the terminal may include, in channel state information, a valueof 7 bits corresponding to a section in which a CSI-RS RSRP measurementresult having a largest value of a plurality of CSI-RS RSRP measurementresults is included, from a table configured in advance in which valuesin the range of [−140, −44] dBm are broken down and set at 1 dBintervals. Further, the terminal may include, in channel stateinformation, remaining CSI-RS RSRP measurement results except for theCSI-RS RSRP measurement result having the largest value of the pluralityof CSI-RS RSRP measurement results using a table for indicating adifferential CSI-RS RSRP measurement result. Here, the reference RSRPvalue is determined as the largest value, and in another example, thereference RSRP value may be determined as a smallest value.

The table for indicating the differential CSI-RS RSRP measurement resultis made up of 16 sections broken down at 2 bB intervals indicating adifference from the CSI-RS RSRP measurement result having the largestvalue of the plurality of CSI-RS RSRP measurement results. Accordingly,the remaining CSI-RS RSRP measurement results may be included in thechannel state information as values in 4 bits. The table for indicatingthe differential CSI-RS RSRP measurement result is described as beingconfigured in 4 bits; however, any values smaller than 7 bits may beavailable.

FIGS. 16 and 17 are diagrams illustrating examples of differential RSRPtables according to embodiments of the present disclosure.

Referring to FIG. 16 , the differential RSRP table may be configured in4 bits. That is, an RSRP table 1600 of 4 bits may be configured at 1 dBintervals. In another example, an RSRP table 1610 of 5 bits may beconfigured at 1 dB intervals.

In addition, differential RSRP tables may be configured at 2 dBintervals, or the like, and be variously configured in 3 bits, 4 bits, 5bits, 6 bits, or the like. In another example, an interval of a sectionfor each bit may be differentially configured. For example, inrespective cases of 3 bits, 4 bits, and 5 bits, correspondingdifferential RSRP tables may be configured at 3 dB intervals, 2 dBintervals, and 1 dB intervals, respectively.

Referring to FIG. 17 , a differential RSRP table is configured in 4bits, configured at 2 dB intervals, and thus, configured with 16sections.

As described above, when it is determined that the group-based beamreporting is used, the channel state information may include one valueof 7 bits indicating a largest value of a plurality of CSI-RS RSRPmeasurement results and one or more values of 4 bits indicating adifference from the largest value. Further, the application of thedifferential RSRP measurement result may be performed only in acorresponding identical beam group.

Through this, the terminal can reduce the overload of an amount of dataincluded in channel state information that may occur when indicatingeach of RSRP values in 7 bits.

Hereinafter, operation of a base station capable of performing theembodiments of the present disclosure described above is brieflydiscussed with reference to the accompanying drawings.

FIG. 18 is a flow diagram illustrating operation of a base stationaccording to embodiments of the present disclosure.

Referring to FIG. 18 , a method of enabling a base station to receivechannel state information for one or more beams may include transmittingCSI report configuration information to a terminal, at step S1800.

As described above, the CSI reporting configuration information mayinclude group-based beam reporting parameters indicating whethergroup-based beam reporting is configured. For example, when thegroup-based beam reporting parameter is set to disablement, thegroup-based beam reporting parameters may further include a valueindicating the number of measured CSI-RS resources to be included inchannel state information. In addition, the CSI reporting configurationinformation may include various parameters described with reference toFIG. 9 .

The method of receiving the channel state information may includereceiving channel state information including two or more CSI-RS RSRPmeasurement results when group-based beam reporting is determined basedon the CSI reporting configuration information, at step S1810.

In this case, the CSI-RS RSRP measurement results may be included in thechannel state information as values in a table configured in advance inthe terminal. For example, the table configured in advance may include atable for indicating one CSI-RS RSRP measurement result and a table forindicating at least one differential CSI-RS RSRP measurement result.

For example, the channel state information may include a value of 7 bitscorresponding to a section in which a CSI-RS RSRP measurement resulthaving a largest value of two or more CSI-RS RSRP measurement results isincluded, from a table configured in advance for indicating one CSI-RSRSRP measurement result in which values in the range of [−140, −44] dBmare broken down and set at 1 dB intervals. Further, the channel stateinformation may include values of 4 bits selected from the table forindicating the differential CSI-RS RSRP measurement result for remainingCSI-RS RSRP measurement results except for the CSI-RS RSRP measurementresult having the largest value of the two or more CSI-RS RSRPmeasurement results.

The table for indicating the differential CSI-RS RSRP measurement resultmay be made up of 16 sections divided at 2 bB intervals indicating adifference from the CSI-RS RSRP measurement result having the largestvalue of the plurality of CSI-RS RSRP measurement results.

In addition, the base station may perform all operations for controllingthe methods of a terminal for transmitting channel state informationdescribed with reference to FIGS. 8 to 17 .

In accordance with the foregoing discussions, when transmitting groupbeam based channel state information through operations of a terminaland a base station, it is possible to provide an effect of preventing anamount of data from being excessively increased.

Hereinafter, a power headroom reporting method of a terminal to which ascheme similar to those of the above embodiments is applied isdiscussed.

<Power Headroom Reporting>

Power headroom reporting procedure is used for providing a base stationwith information on a difference between maximum terminal transmissionpower and estimated power for UL-SCH transmission or SRS transmissionfor each activated serving cell. Further, it is used for providinginformation on maximum terminal power and estimated power for UL-SCH andPUCCH transmissions in a SpCell and a PUCCH SCell.

Information on a period, a delay and mapping for the power headroomreporting may be indicated by a base station, and the RRC layer controlsthe power headroom reporting based on two timers. Here, the two timersare dl-PathlossChange and prohibitPHR-Timer.

The power headroom reporting is triggered by at least one of thefollowing cases.

-   -   The prohibitPHR-Timer expires, or the prohibitPHR-Timer expires        and dl-PathlossChange parameter error path loss information is        changed.    -   The dl-PathlossChange expires.    -   Power headroom reporting function is configured or reconfigured        from a higher layer.    -   A SCell is activated, or added.    -   An uplink resource is assigned, etc.

FIGS. 19 and 20 are diagrams illustrating a MAC control element (CE) forpower headroom reporting according to embodiments of the presentdisclosure.

Referring to FIG. 19 , in the power headroom reporting, the MAC controlelement may be identified by a MAC PDU subheader in which a logicalchannel identifier (LCID) is present.

Here, R represents a reserved bit, and is set as 0. PH represents apower headroom field and includes a value of a power headroom level. ThePH is configured in 6 bits, and the power headroom level is determinedas a value mapped in a table configured in advance.

For example, the table for the power headroom level may be configured asin Table 2 below.

TABLE 2 PH Power Headroom Level 0 POWER_HEADROOM_0 1 POWER_HEADROOM_1 2POWER_HEADROOM_2 3 POWER_HEADROOM_3 . . . . . . 60 POWER_HEADROOM_60 61POWER_HEADROOM_61 62 POWER_HEADROOM_62 63 POWER_HEADROOM_63

Meanwhile, a power headroom reporting range may be set as a range of −23to +40 dB, and be mapped with a power headroom level in Table 3 below.

TABLE 3 Reported value Measured quantity value (dB) POWER_HEADROOM_0 −23≤ PH < −22 POWER_HEADROOM_1 −22 ≤ PH < −21 POWER_HEADROOM_2 −21 ≤ PH <−20 POWER_HEADROOM_3 −20 ≤ PH < −19 POWER_HEADROOM_4 −19 ≤ PH < −18POWER_HEADROOM_5 −18 ≤ PH < −17 . . . . . . POWER_HEADROOM_57 34 ≤ PH <35 POWER_HEADROOM_58 35 ≤ PH < 36 POWER_HEADROOM_59 36 ≤ PH < 37POWER_HEADROOM_60 37 ≤ PH < 38 POWER_HEADROOM_61 38 ≤ PH < 39POWER_HEADROOM_62 39 ≤ PH < 40 POWER_HEADROOM_63 PH ≥ 40

Referring to FIG. 20 , a single entry power headroom MAC CE may beidentified by a MAC PDU subheader together with an LCID.

Here, R represents a reserved bit, and is set as 0. PH represents afield for indicating a power headroom level, and is configured in 6bits. Pcmax,c represents a value of maximum terminal transmission powerused in a previous PH field calculation, and may be configured in 6bits.

Table 4 below may be used for a value included in the PH field PH, andTable 5 below may be used for the Pcmax,c.

TABLE 4 PH Power Headroom Level 0 POWER_HEADROOM_0 1 POWER_HEADROOM_1 2POWER_HEADROOM_2 3 POWER_HEADROOM_3 . . . . . . 60 POWER_HEADROOM_60 61POWER_HEADROOM_61 62 POWER_HEADROOM_62 63 POWER_HEADROOM_63

TABLE 5 P_(CMAXc) Nominal UE transmit power level 0 PCMAX_C_00 1PCMAX_C_01 2 PCMAX_C_02 . . . . . . 61 PCMAX_C_61 62 PCMAX_C_62 63PCMAX_C_63

In the present disclosure, a method is provided for breaking down powerheadroom steps used when reporting power headroom information to a basestation. As described above, in the 4G LTE, to report the power headroominformation, a power headroom is broken down into 64 steps of 0 to 63corresponding to from −23 dB to 40 dB at 1 dB intervals in 6 bits. Inthe LTE, one base station covers a radius of several hundreds of metersto several kilometers. In contrast, in the 5G, there is a possibilitythat each base station may cover only a radius of several tens of metersto several hundreds of meters using a small cell. Thus, a change innumerical values related to power headroom reporting is needed due to areduced cell size, compared with the LTE. According to this, a powerheadroom reporting method is provided in which after breaking down powerheadroom (PH) steps into 32 steps in 5 bits, 48 steps in 6 bits, 64steps in 6 bits, 128 steps in 7 bits, or the like, a measurement powervalue corresponding to each step is assigned to any range or numericvalue.

Embodiment 1

Power headroom information may be included in a MAC CE using Table 6below in which a power headroom is configured with 5 bits and brokendown into 32 sections.

For example, in the Table 6, power headroom steps are broken down into32 steps in 5 bits. Measurement power values corresponding to a powerheadroom (PH) to be reported may be resulted from breaking down a rangeof −23˜23 dB on a 1 dB or 2 dB basis at different intervals, and anactual measurement power value may be any range or numeric valuedifferent from this.

TABLE 6 Reported Value Measured Quantity Valued(dB)

POWER_HEADROOM_0 −23 ≤ PH < −21 2 dB POWER_HEADROOM_1 −21 ≤ PH < −19 2dB POWER_HEADROOM_2 −19 ≤ PH < −17 2 dB POWER_HEADROOM_3 −17 ≤ PH < −152 dB POWER_HEADROOM_4 −15 ≤ PH < −13 2 dB POWER_HEADROOM_5 −13 ≤ PH <−11 2 dB POWER_HEADROOM_6 −11 ≤ PH < −9 2 dB POWER_HEADROOM_7 −9 ≤ PH <−7 2 dB POWER_HEADROOM_8 −7 ≤ PH < −6 2 dB . . . . . . POWER_HEADROOM_227 ≤ PH < 8 1 dB POWER_HEADROOM_23 8 ≤ PH < 9 1 dB POWER_HEADROOM_24 9 ≤PH < 11 2 dB POWER_HEADROOM_25 11 ≤ PH < 13 2 dB POWER_HEADROOM_26 13 ≤PH < 15 2 dB POWER_HEADROOM_27 15 ≤ PH < 17 2 dB POWER_HEADROOM_28 17 ≤PH < 19 2 dB POWER_HEADROOM_29 19 ≤ PH < 21 2 dB POWER_HEADROOM_30 21 ≤PH < 23 2 dB POWER_HEADROOM_31 PH ≥ 23 2 dB

That is, a power headroom level for power headroom reporting may beconfigured at a plurality of intervals rather than an identicalinterval.

Embodiment 2

In another embodiment, power headroom steps may be broken down into 64steps in 6 bits. Measurement power values corresponding to a powerheadroom (PH) to be reported may be resulted from breaking down a rangeof −23˜40 dB on a 2 dB or 0.5 dB basis at different intervals, and anactual measurement power value may be any range or numeric valuedifferent from this.

TABLE 7 Reported Value Measured Quantity Valued(dB)

POWER_HEADROOM_0 −23 ≤ PH < −21 2 dB POWER_HEADROOM_1 −21 ≤ PH < −19 2dB POWER_HEADROOM_2 −19 ≤ PH < −17 2 dB . . . . . . POWER_HEADROOM_9 −5≤ PH < −3 2 dB POWER_HEADROOM_10 −3 ≤ PH < −1 2 dB POWER_HEADROOM_11 −1≤ PH < −0.5 0.5 dB POWER_HEADROOM_12 −0.5 ≤ PH < 0 0.5 dBPOWER_HEADROOM_13 0 ≤ PH < 0.5 0.5 dB POWER_HEADROOM_14 0.5 ≤ PH < 1 0.5dB . . . . . . POWER_HEADROOM_50 18.5 ≤ PH < 19 0.5 dB POWER_HEADROOM_5119 ≤ PH < 19.5 0.5 dB POWER_HEADROOM_52 19.5 ≤ PH < 20 0.5 dBPOWER_HEADROOM_53 20 ≤ PH < 22 2 dB POWER_HEADROOM_54 22 ≤ PH < 24 2 dB. . . . . . POWER_HEADROOM_60 34 ≤ PH < 36 2 dB POWER_HEADROOM_61 36 ≤PH < 38 2 dB POWER_HEADROOM_62 38 ≤ PH < 40 2 dB POWER_HEADROOM_63 PH ≥40 2 dB

That is, an interval between PH values included in a power headroomlevel may be configured with a plurality of intervals, and one or moreintervals between PH values around a center value may be configured at anarrower interval.

Embodiment 3

In another embodiment, power headroom steps may be broken down into 64steps in 6 bits. Measurement power values corresponding to a powerheadroom (PH) to be reported may be resulted from breaking down a rangeof −10˜21 dB on a 0.5 dB basis at a uniform interval, and an actualmeasurement power value may be any range or numeric value different fromthis.

TABLE 8 Reported Value Measured Quantity Valued(dB) POWER_HEADROOM_0 −10≤ PH < −9.5 POWER_HEADROOM_1 −9.5 ≤ PH < −9 POWER_HEADROOM_2 −9 ≤ PH <−8.5 POWER_HEADROOM_3 −8.5 ≤ PH ≤ −8 . . . . . . POWER_HEADROOM_61 20 ≤PH < 20.5 POWER_HEADROOM_62 20.5 ≤ PH < 21 POWER_HEADROOM_63 PH ≥ 21

Here, an interval is configured to maintain a uniform interval of 0.5dB.

Embodiment 4

In another embodiment, power headroom steps may be broken down into 48steps in 6 bits. Measurement power values corresponding to a powerheadroom (PH) to be reported may be resulted from breaking down a rangeof −17-90 dB on a 1 dB basis at a uniform interval, and an actualmeasurement power value may be any range or numeric value different fromthis.

TABLE 9 Reported Value Measured Quantity Valued(dB) POWER_HEADROOM_0 −17≤ PH < −16 POWER_HEADROOM_1 −16 ≤ PH < −15 POWER_HEADROOM_2 −15 ≤ PH <−14 . . . . . . POWER_HEADROOM_46 28 ≤ PH < 29 POWER_HEADROOM_47 PH ≥ 30POWER_HEADROOM_48 Reserved . . . . . . POWER_HEADROOM_62 ReservedPOWER_HEADROOM_63 Reserved

Embodiment 5

In another embodiment, power headroom steps may be broken down into 128steps in 7 bits. Measurement power values corresponding to a powerheadroom (PH) to be reported may be resulted from breaking down a rangeof −23˜40 dB on a 0.5 dB basis at a uniform interval, and an actualmeasurement power value may be any range or numeric value different fromthis.

TABLE 10 Reported Value Measured Quantity Valued(dB) POWER_HEADROOM_0−23 ≤ PH < −22.5 POWER_HEADROOM_1 −22.5 ≤ PH < −22 POWER_HEADROOM_2 −22≤ PH < −21.5 POWER_HEADROOM_3 −21.5 ≤ PH < −21 . . . . . .POWER_HEADROOM_125 39 ≤ PH < 39.5 POWER_HEADROOM_126 39.5 ≤ PH < 40POWER_HEADROOM_127 PH ≥ 40

In addition, a table for the power headroom reporting described abovemay be configured by combining at least two of the Embodiments 1 to 5.

<CSI Reporting Rule>

In the case of CSI reporting, a priority may be determined according tovarious factors. For example, when periodic CSI reporting and aperiodicCSI reporting etc. are transmitted in various schemes, a priority of CSIreporting may be set according to a specific rule, and through this, theCSI reporting can be effectively transmitted using a limited resource.

A typical equation for determining a CSI priority is as follows.

Pri _(tCSI)(y,k,c,s)=2·16·M _(s) ·y+16·M _(s) ·k+M _(s) ·c+s

Here, values of y, k, c, s, and M_s may be determined according to eachtype of CSI reporting. For example, a value of c may be differentaccording to types of CSI reports. A case of c=1 denotes CSI reporting,and a case of c=31 denotes beam reporting.

In this case, in the case of employing such typical CSI rule, as thevalue of c is increased, priority itself may not be effectively set. Forexample, comparing with the CSI reporting, since the beam reporting hasc=31 that is relatively high, while having a low priority, the beamreporting may have a higher priority value.

Further, in addition to this situation, since values of c, s and M_s infuture releases may be increased, there may be a possibility that thetypical priority value equation causes some problems.

To address this issue, various equations for priority calculation areprovided below.

Embodiment 1

Pri _(CSI)(y,k,c,s)=2*32*M _(s) *y+32*M _(s) *k+M _(s) *c+s

Here, c is a number from 0 to 31. Accordingly, in the previous equation,when the coefficient is changed from 16 to 32. priority rules are alwayssatisfied.

Embodiment 2

Pri _(CSI)(y,k,c,s)=2*64*M _(s) *y+64*M _(s) *k+M _(s) *c+s

Since the value of c may be increased in the future, the coefficient maybe set to 64 in case the value of c is increased from 0 to 63.

Embodiment 3

Pri _(CSI)(y,k,c,s)=2*length(c)*M _(s) *y+length(c)*M _(s) *k+M _(s)*c+s

Thus, the coefficient may be set to depend on a length of c so that boththe Embodiments 1 and 2 can be included.

Embodiment 4

Pri _(CSI)(y,k,c,s)=2*16*M _(s) *y+16*M _(s) *k+M _(s)*log 2(c)+log 2(s)

When the value of c is set to be smaller than 65536 and the value of sis smaller than 2^({circumflex over ( )}Ms), this equation enablespriority rules to be always satisfied.

$\begin{matrix}{{{Pri}_{CSI}\left( {y,k,c,s} \right)} = {{2*16*M_{s}*y} + {16*M_{s}*k} + {M_{s}*\frac{c}{2}} + \frac{s}{2}}} & {{Embodiment}5}\end{matrix}$

In the typical priority equation, in order to minimize changes in othervalues, c and s may be divided by 2.

$\begin{matrix}{{{Pri}_{CSI}\left( {y,k,c,s} \right)} = {{2*16*M_{s}*y} + {16*M_{s}*k} + {M_{s}*\frac{c}{4}} + \frac{s}{4}}} & {{Embodiment}6}\end{matrix}$

In the typical priority equation, in order to minimize changes in othervalues, c and s may be divided by 4.

$\begin{matrix}{{{Pri}_{CSI}\left( {y,k,c,s} \right)} = {{2*2^{n}*M_{s}*y} + {2^{n}*M_{s}*k} + {M_{s}*\frac{c}{2^{m}}} + \frac{s}{2^{m}}}} & {{Embodiment}7}\end{matrix}$

In the typical priority equation, in order to minimize changes in othervalues, c and s may be divided 2 to the power of m. Here, m is any realnumber.

Through various Embodiments described above, it is possible to solve theproblem that a priority value and an actual priority may be different,the priority equations can be established so that they can be used evenwhen the value of c is increased.

<SSB and PDCCH Power Offset Configuration Method>

Predetermined power offsets of a synchronization signal block (SSB) anda physical downlink control channel (PDCCH) enable Rx-AGC of a terminal.On the other hand, unlimited power offsets cause unnecessary performancedegradation of the terminal. Accordingly, it is necessary to determine arange of limiting power offsets of the SSB and the PDCCH.

As described above, a synchronization signal includes in the SSB made upof a primary synchronization signal (PSS), a secondary synchronizationsignal (SSS) and a physical broadcast channel (PBCH).

In the LTE, the PSS uses 3 sequences indicating one or more physicallayer identifiers in each group of a cell. The PSS is based on afrequency domain ZC sequence with a length of 63. The PSS is mapped tothe sixth symbol in slots 0 and 10 of each radio frame in 72 subcarrierscentered on the middle DC subcarrier.

The SSS is based on maximum length sequences (m-sequences), and in theLTE, the SSC1 and the SSC2 are two codes that are two different cyclicshifts of an M sequence with a single length of 31. Each SSS sequence isconfigured by interleaving two second synchronization codes each havinga length of 31 and modulated with BPSK in the frequency domain. The twocodes are alternately placed between first and second SSS transmissionsin each radio frame. This allows a terminal to determine a 10 ms radioframe timing from a single observation of the SSS. Such SSS is mapped tothe fifth symbol in slots 0 and 10 of each radio frame in 72 subcarrierscentered on the middle DC subcarrier.

There are 1008 different physical cell identities (PCI) acquired througha synchronization signal, and a terminal can determine a PCI accordingto the following equation.

N _(ID) ^(cell)=3N _(ID) ⁽¹⁾ +N _(ID) ⁽²⁾

Here,N _(ID) ⁽¹⁾∈{0,1, . . . ,335} and N _(ID) ⁽²⁾∈{0,1,2}.

Meanwhile, it is necessary for a power offset between the SSB and thePDCCH to be limited to a certain level. This helps reception automaticgain control (AGC) to be effectively performed.

To do this, a terminal may receive power offset indication informationbetween the SSB and the PDCCH from a base station. Such indicationinformation may be received through system information or RRCinformation.

For example, the terminal may receive a value with a dynamic rangewithin 3 dB from the base station.

In another example, the terminal may receive indication information witha plurality of values within 3 dB from the base station.

In another example, the terminal may receive indication informationindicating 0 or 3 dB.

Unlike this, the power offset value may be fixed.

For example, the power offset may be configured to be fixed at 3 dB inadvance.

In another example, the power offset value may be configured to be fixedat any value within a range of 0 to 3 dB in advance.

<PDCCH Search Space Configuration Method>

Embodiments described below relate to methods of determining candidatesdropped in a process of mapping a search space of a downlink controlchannel (PDCCH) in wireless communication systems.

The PDCCH may be used to transmit downlink control information. Forexample, the downlink control information may include schedulinginformation, power control command information, and the like, and mayinclude a transport port format, HARQ information, and the like.

A terminal performs PDCCH monitoring to receive the PDCCH. To do this,the terminal monitors a search space to receive the PDCCH.

The resource assignment of the PDCCH occurs from control channel element(CCE) perspective. One CCE is made up of 9 resource element groups(REG), and one REG is made up of 4 REs. That is, a single CCE is made upof 36 REs. One PDCCH is transferred by a plurality of consecutive CCEs.The number of CCEs for the PDCCH depends on a format of the PDCCH. Arelationship between the PDCCH format and the number of CCEs needed fortransferring the PDCCH is as follows.

-   -   PDCCH Format 0: Requires 1 CCE=Aggregation Level 1 (2{circumflex        over ( )}PDCCH Format=2{circumflex over ( )}0=1)    -   PDCCH Format 1: Requires 2 CCE=Aggregation Level 2 (2{circumflex        over ( )}PDCCH Format=2{circumflex over ( )}1=2)    -   PDCCH Format 2: Requires 4 CCE=Aggregation Level 4 (2{circumflex        over ( )}PDCCH Format=2{circumflex over ( )}2=4)    -   PDCCH Format 3: Requires 8 CCE=Aggregation Level 8 (2{circumflex        over ( )}PDCCH Format=2{circumflex over ( )}3=8)

The number of consecutive CCEs needed for transferring one PDCCH isreferred to as “aggregation level” Table 11 represents the PDCCH format,the number of CCEs, the number of REGs and the number of PDCCH bits.

TABLE 11 PDCCH Number of Number of resource- Number of format CCEselement groups PDCCH bits 0 1 9 72 1 2 18 144 2 4 36 288 3 8 72 576

A terminal searches a plurality of spaces to monitor a PDCCH on a PDCCHresource A possible location in which the PDCCH is transmitted isdifferent according to whether the PDCCH is UE-specific(terminal-specific) or common, and depends on which aggregation level isused. All possible locations for the PDCCH is referred to as “searchspace”, and each possible location is referred to as “PDCCH candidate”.

The search space represents a set of CCE locations for allowing aterminal to find its PDCCH. Each PDCCH transfers one DCI and isidentified by an RNTI. The RNTI is implicitly encoded in CRC attachmentof the DCI.

There are two types of search spaces, that is, a common search space anda UE-specific (terminal-specific) search space. The terminal is requiredto monitor both the common search space and the UE-specific searchspace. There may occur an overlap between the common search space andthe UE-specific search space for a terminal.

-   -   The common search space transfers DCI being common to all        terminals. For example, the common search space may deliver        system information (using SI-RNTI), paging (P-RNTI), a PRACH        response (RA-RNTI) or an UL TPC command (TPC-PUCCH/PUSCH-RNTI).        The terminal monitors the common search space using terminal        aggregation levels 4 and 8. A maximum number of CCEs present in        the common search space is 16.    -   The UE-specific search space may deliver a terminal-specific DCI        using a C-RNTI assigned to the terminal, semi-permanent        scheduling (SPS C-RNTI), or initial assignment (temporary        C-RNTI). The terminal monitors the UE-specific search space in        all aggregation levels (1, 2, 4 and 8).

Table 12 below represents a relationship between the search space andPDCCH candidate monitoring.

TABLE 12 Search space S_(k) ^((L)) Aggregation Size Number of PDCCH Typelevel L [in CCEs] candidates M^((L)) UE- 1 6 6 specific 2 12 6 4 8 2 816 2 Common 4 16 4 8 16 2

In such situation, a base station may apply a PDCCH candidate mappingrule in order to transmit a PDCCH to a terminal. From terminalperspective, it may be recognized as a PDCCH candidate drop rule.Accordingly, in order to allow all of the terminal and the base stationto recognize an equal PDCCH candidate mapping rule or drop rule in anequal condition, it is necessary to introduce a PDCCH candidate priorityrule.

For example, the common search space (CSS) has a higher priority thanthe UE-specific search space (USS), and a PDCCH candidate is mapped tothe CSS earlier than the USS. Due to some limitations to blind decodingand the CCE, when a CSS occurs in a slot together with a USS, a terminalmonitors the CSS earlier than the USS. That is, the terminal drops PDCCHcandidates for the USS prior to the CSS. Further, it is necessary todetermine a PDCCH candidate priority rule in a search space set/type.

The terminal may early perform blind decoding for PDCCH candidates witha higher priority based on the PDCCH candidate priority rule. When thenumber of blind decodings or the number of CCEs not being overlappedexceeds based on the PDCCH candidate priority rule, the terminal dropsremaining PDCCH candidates.

As such, in the 5G NR, as the number of UEs increases, it is needed totransmit a larger number of PDCCHs. Accordingly, CCEs assigned for thePDCCHs also becomes larger, and in mapping this, there may occur a casethat is required to filter one or more candidates. In this case, ascheme of dropping candidates is needed.

Hereinafter, embodiments of PDCCH candidate drop schemes are discussed.

1. Preferentially drop a UE-specific search space (USS) over a commonsearch space (CSS).

Common DCI for all terminals are delivered through the common searchspace. On the other hand, DCI for each terminal is delivered through theUE-specific search space. Accordingly, the common search spacedelivering the common DCI is preferentially transferred.

2. Preferentially drop a lower aggregation level.

Relatively larger CCE is assigned to a high aggregation level.Accordingly, if the high aggregation level is dropped, a large amount ofCCE cannot be designated as candidates at once. This may cause too muchCCE to be dropped. Therefore, preferentially drop a lower aggregationlevel.

3. Evenly drop rather than preferentially dropping a higher SS index.

Regardless of an index of a search space, drop a candidate to be evenlydistributed. For example, the dropping may be performed as follows.

{circle around (1)} In case of #SS≠n (mod 4), all drop. (n=0˜3)

{circle around (2)} In case of #SS≠n (mod 8), all drop. (n=0˜7)

{circle around (3)} In case of #SS≠n (mod 16), all drop. (n=0˜15)

4. Considering both the rule 1 and the rule 3.

Evenly distribute CSS candidates while remaining CSS candidates as muchas possible. For example, in the CSS, one or more candidates areselected based on multiples of 2, and in the USS, one or more candidatesare selected based on multiples of 16.

Specifically, candidates may be selected as follows.

{circle around (1)} In the common search space, only multiples of 2 areselected as candidates, and in the UE-specific search space, onlymultiples of 8 are selected as candidates.

{circle around (2)} In the common search space, only multiples of 2 areselected as candidates, and in the UE-specific search space, onlymultiples of 16 are selected as candidates.

In addition, candidates may be selected by combining at least two ormore of the rules 1 to 4.

As described above, priorities for PDCCH candidates may be determinedaccording to the various schemes described above.

Hereinafter, configurations of a terminal and a base station to whichall of the embodiments described above can be applied will be describedbriefly with reference to accompanying drawings.

FIG. 21 is a block diagram illustrating a terminal in accordance withembodiments of the present disclosure.

Referring to FIG. 21 , the terminal 2100 is provided for transmittingchannel state information for one or more beams, the terminalcomprising: a receiver 2130 receiving CSI reporting configurationinformation from a base station; a controller 2110 determining whethergroup-based beam reporting is configured based on the CSI reportingconfiguration information, and measuring RSRP for one or more CSI-RSsreceived through one or more CSI-RS resources; and a transmitter 2120transmitting, to the base station, channel state information including avalue in a table configured in advance based on whether the group-basedbeam reporting is used and one or more CSI-RS RSRP measurement results.

When the group-based beam reporting parameter is set to enablement, or avalue indicating the number of measured CSI-RS resources to be includedin channel state information is set as a value exceeding 1, thecontroller 2110 may determine that the group-based beam reporting isused.

When it is determined that the group-based beam reporting is not used,the transmitter 2120 may include, in channel state information, a valueof 7 bits corresponding to a section in which one CSI-RS RSRPmeasurement result is included from a pre-configured table in whichvalues in the range of [−140, −44] dBm are broken down and set at 1 dBintervals, and then transmit the channel state information including thevalue of 7 bits.

When it is determined that the group-based beam reporting is used, thetransmitter 2120 may include, in channel state information, a value of 7bits corresponding to a section in which a CSI-RS RSRP measurementresult having a largest value of a plurality of CSI-RS RSRP measurementresults is included, from a table configured in advance in which valuesin the range of [−140, −44] dBm are broken down and set at 1 dBintervals. Further, the transmitter 2120 may include, in channel stateinformation, remaining CSI-RS RSRP measurement results except for theCSI-RS RSRP measurement result having the largest value of the pluralityof CSI-RS RSRP measurement results using a table for indicating adifferential CSI-RS RSRP measurement result.

The table for indicating the differential CSI-RS RSRP measurement resultmay be made up of 16 sections broken down at 2 bB intervals indicating adifference from the CSI-RS RSRP measurement result having the largestvalue of the plurality of CSI-RS RSRP measurement results. The remainingCSI-RS RSRP measurement results may be included in the channel stateinformation as values in 4 bits.

The CSI reporting configuration information includes group-based beamreporting parameters indicating whether group-based beam reporting isused. When the group-based beam reporting parameter is set todisablement, the group-based beam reporting parameters may furtherinclude a value indicating the number of measured CSI-RS resources to beincluded in channel state information.

In addition, the controller 2110 controls overall operations of terminal2100 required to perform operations for transmitting channel stateinformation according to whether the group-based beam reporting is used,and required to perform all or some of the embodiments of the presentdisclosure.

Further, the controller 2100 controls overall operations of the terminal2100 needed for performing the embodiments of the present disclosure forthe power headroom reporting, the channel state information transmissionpriority setting, the power offset configuration of the SSB and thePDCCH, and the PDCCH search space configuration.

The transmitter 2120 and the receiver 2130 are used to transmit, to thebase station and receive from the base station, signals, messages, anddata necessary for performing embodiments of the present disclosure.

FIG. 22 is a block diagram illustrating a base station according toembodiments of the present disclosure.

Referring to FIG. 22 , the base station 2200 comprises: a transmitter2220 transmitting CSI reporting configuration information to a terminal;and when it is determined that group-based beam reporting is used basedon the CSI reporting configuration information, a receiver 2230receiving channel state information including two or more CSI-RS RSRPmeasurement results.

The CSI-RS RSRP, such as the two or more CSI-RS RSRP measurementresults, is included in the channel state information as a value in atable configured in advance in the terminal, and the table configured inadvance may include a table for indicating one CSI-RS RSRP measurementresult and a table for indicating at least one differential CSI-RS RSRPmeasurement result.

When it is determined that the group-based beam reporting is not used,the receiver 2230 may receive by including, in the channel stateinformation, a value of 7 bits corresponding to a section in which oneCSI-RS RSRP measurement result is included from a table configured inadvance in which values in the range of [−140, −44] dBm are broken downand set at 1 dB intervals.

When it is determined that the group-based beam reporting is used, thereceiver 2230 may receive, by including, in channel state information, avalue of 7 bits corresponding to a section in which a CSI-RS RSRPmeasurement result having a largest value of a plurality of CSI-RS RSRPmeasurement results is included, from a table configured in advance inwhich values in the range of [−140, −44] dBm are broken down and set at1 dB intervals. Further, the receiver 2230 may receive by including, inchannel state information, remaining CSI-RS RSRP measurement resultsexcept for the CSI-RS RSRP measurement result having the largest valueof the plurality of CSI-RS RSRP measurement results using a table forindicating a differential CSI-RS RSRP measurement result.

The table for indicating the differential CSI-RS RSRP measurement resultmay be made up of 16 sections broken down at 2 bB intervals indicating adifference from the CSI-RS RSRP measurement result having the largestvalue of the plurality of CSI-RS RSRP measurement results. The remainingCSI-RS RSRP measurement results may be included in the channel stateinformation as values in 4 bits.

The CSI reporting configuration information includes group-based beamreporting parameters indicating whether group-based beam reporting isconfigured. When the group-based beam reporting parameter is set todisablement, the group-based beam reporting parameters may furtherinclude a value indicating the number of measured CSI-RS resources to beincluded in channel state information.

In addition, the controller 2210 controls overall operations of the basestation 2200 required to perform operations for receiving channel stateinformation according to whether the group-based beam reporting is used,and required to perform all or some of the embodiments of the presentdisclosure.

Further, the controller 2210 controls overall operations of the basestation 2200 needed for performing the embodiments of the presentdisclosure for the power headroom reporting, the channel stateinformation transmission priority setting, the power offsetconfiguration of the SSB and the PDCCH, and the PDCCH search spaceconfiguration.

The transmitter 2220 and the receiver 2230 are used to transmit, to aterminal and receive from the terminal, signals, messages, and datanecessary for performing embodiments of the present disclosure.

The embodiments described above may be supported by the standarddocuments disclosed in at least one of the wireless access systems IEEE802, 3GPP and 3GPP2. That is, the steps, configurations, and parts notdescribed in the present embodiments for clarifying the technical ideamay be supported by standard documents described above. In addition, allterms disclosed herein may be described by the standard documentsdescribed above.

The embodiments described above may be implemented by various means. Forexample, the embodiments of the present disclosure may be implemented byhardware, firmware, software, or a combination thereof.

In the case of hardware implementation, the method according toembodiments may be implemented by one or more of application specificintegrated circuits (ASICs), digital signal processors (DSPs), digitalsignal processing devices (DSPDs), programmable logic devices (PLDs)(Field Programmable Gate Arrays), a processor, a controller, amicrocontroller, a microprocessor, or the like.

In the case of an implementation by firmware or software, the methodaccording to the embodiments may be implemented in the form of anapparatus, a procedure, or a function for performing the functions oroperations described above. The software code may be stored in a memoryand driven by the processor. The memory may be located inside or outsideof the processor, and may transmit data to the processor or receive datafrom the processor by various well-known means.

The terms “system”, “processor”, “controller”, “component”, “module”,“interface”, “model”, “unit”, or the like described above may generallyrefer to computer-related entity hardware, a combination of hardware andsoftware, software, or running software. For example, such elementsdescribed above may be, but not limited to, a process driven by theprocessor, a control processor, an entity, a running thread, a programand/or a computer. For example, when an application runs on a controlleror a processor, all of the application, the controller or the processorcan become one element. One or more elements or components may be placedin a processor and/or an executed thread, the elements or components maybe placed in one device or apparatus (e.g., a system, a computingdevice, etc.), or placed distributed in two or more devices orapparatuses.

The forgoing has been presented to best explain the embodiments andexamples and thereby to enable any person skilled in the art to make anduse the invention as claimed. Various modifications, additions andsubstitutions to the described embodiments and examples will be readilyapparent to those skilled in the art without departing from the spiritand scope of the present disclosure. The specific embodiments andexamples described herein are to be understood as particularly gracefulimplementations of the claimed invention in an effort to illustraterather than limit technical principles of the present disclosure. Thus,the breadth and scope of the present disclosure should not be limited byany of the above-described embodiments and examples. Rather, the scopeof protection of the present disclosure should be construed based on thefollowing claims, and all technical ideas or principles within the scopeof equivalents thereof should be construed as being included within thescope of the present disclosure.

What is claimed is:
 1. A method of a terminal for transmitting channelstate information for one or more beams, the method comprising:determining whether group-based beam reporting is configured based onchannel state information (CSI) reporting configuration information;measuring reference signal received power (RSRP) for one or more channelstate information reference signals (CSI-RS) received through one ormore CSI-RS resources; and transmitting, to a base station, the channelstate information including a value in a table configured in advancebased on whether the group-based beam reporting is configured and one ormore CSI-RS RSRP measurement results obtained by the measurement,wherein the transmitting of the channel state information to the basestation is performed such that when it is determined that thegroup-based beam reporting is used, the channel state information istransmitted by including a value of 7 bits corresponding to a section inwhich a CSI-RS RSRP measurement result having a largest value of theCSI-RS RSRP measurement results is included, from the table configuredin advance in which values in the range of [−140, −44] dBm are brokendown and set at 1 dB intervals, and including remaining CSI-RS RSRPmeasurement results except for the CSI-RS RSRP measurement result havingthe largest value of the CSI-RS RSRP measurement results using a tablefor indicating a differential CSI-RS RSRP measurement result, andwherein the CSI reporting configuration information includes at leastone of a group-based beam reporting parameter indicating whethergroup-based beam reporting is used and a value indicating a number ofthe measured CSI-RS resources to be included in the channel stateinformation, and wherein the determining for whether the group-basedbeam reporting is configured is performed such that it is determinedthat the group-based beam reporting is used, when the group-based beamreporting parameter is set to enablement or the value indicating thenumber of the measured CSI-RS resources to be included in channel stateinformation is set as a value exceeding
 1. 2. The method according toclaim 1, wherein the table configured in advance includes a table forindicating the one or more CSI-RS RSRP measurement results and the tablefor indicating at least one differential CSI-RS RSRP measurement result.3. The method according to claim 1, wherein the determining for whetherthe group-based beam reporting is configured is performed such that itis determined that the group-based beam reporting is used, when thegroup-based beam reporting parameter is set to enablement.
 4. The methodaccording to claim 1, wherein the determining for whether thegroup-based beam reporting is configured is performed such that it isdetermined that the group-based beam reporting is not used, when thegroup-based beam reporting parameter is set to the disablement and thevalue indicating the number of the measured CSI-RS resources to beincluded in channel state information is set as
 1. 5. The methodaccording to claim 1, wherein the transmitting of the channel stateinformation to the base station is performed such that when it isdetermined that the group-based beam reporting is not used, the channelstate information is transmitted by including a value of 7 bitscorresponding to a section in which the one CSI-RS RSRP measurementresult is included from the table configured in advance in which valuesin the range of [−140, −44] dBm are broken down and set at 1 dBintervals.
 6. The method according to claim 1, wherein the table forindicating the differential CSI-RS RSRP measurement result is made up of16 sections broken down at 2 dB intervals indicating a difference fromthe CSI-RS RSRP measurement result having the largest value of theCSI-RS RSRP measurement results, and wherein the remaining CSI-RS RSRPmeasurement results is included as values in 4 bits.
 7. A terminal fortransmitting channel state information for one or more beams, theterminal comprising: a controller determining whether group-based beamreporting is configured based on channel state information (CSI)reporting configuration information, and measuring reference signalreceived power (RSRP) for one or more channel state informationreference signals (CSI-RS) received through one or more CSI-RSresources; and a transmitter transmitting, to a base station, thechannel state information including a value in a table configured inadvance based on whether the group-based beam reporting is configuredand one or more CSI-RS RSRP measurement results obtained by themeasurement, wherein when it is determined that the group-based beamreporting is used, the transmitter includes, in the channel stateinformation, a value of 7 bits corresponding to a section in which aCSI-RS RSRP measurement result having a largest value of the CSI-RS RSRPmeasurement results is included, from the table configured in advance inwhich values in the range of [−140, −44] dBm are broken down and set at1 dB intervals, and includes remaining CSI-RS RSRP measurement resultsexcept for the CSI-RS RSRP measurement result having the largest valueof the CSI-RS RSRP measurement results using a table for indicating adifferential CSI-RS RSRP measurement result, and wherein the CSIreporting configuration information includes at least one of agroup-based beam reporting parameter indicating whether group-based beamreporting is used, and a value indicating a number of the measuredCSI-RS resources to be included in the channel state information,wherein the determining for whether the group-based beam reporting isconfigured is performed such that it is determined that the group-basedbeam reporting is used, when the group-based beam reporting parameter isset to enablement or the value indicating the number of the measuredCSI-RS resources to be included in channel state information is set as avalue exceeding
 1. 8. The terminal according to claim 7, wherein whenthe group-based beam reporting parameter is set to enablement, thecontroller determines that the group-based beam reporting is used. 9.The terminal according to claim 7, wherein when it is determined thatthe group-based beam reporting is not used, the transmitter transmitsthe channel state information including a value of 7 bits correspondingto a section in which the one CSI-RS RSRP measurement result is includedfrom the table configured in advance in which values in the range of[−140, −44] dBm are broken down and set at 1 dB intervals.
 10. Theterminal according to claim 7, wherein the table for indicating thedifferential CSI-RS RSRP measurement result is made up of 16 sectionsbroken down at 2 dB intervals indicating a difference from the CSI-RSRSRP measurement result having the largest value of the CSI-RS RSRPmeasurement results, and wherein the remaining CSI-RS RSRP measurementresults is included as values in 4 bits.